Shore Up

Target creature you control gets +1/+1 and gains hexproof until end of turn. Untap it. (It can't be the target of spells or abilities your opponents control.)

Vodalian Hexcatcher

Flash
Other Merfolk you control get +1/+1.
Sacrifice a Merfolk: Counter target noncreature spell unless its controller pays {1}.

Soothsayer Adept

{1}{U}, {T}: Draw a card, then discard a card.

Shell Shield

Kicker {1} (You may pay an additional {1} as you cast this spell.)
Target creature you control gets +0/+3 until end of turn. If this spell was kicked, that creature also gains hexproof until end of turn. (It can't be the target of spells or abilities your opponents control.)

Emperor Mihail II

You may look at the top card of your library any time.
You may cast Merfolk spells from the top of your library.
Whenever you cast a Merfolk spell, you may pay {1}. If you do, create a 1/1 blue Merfolk creature token.

Deepwater Hypnotist

Inspired — Whenever Deepwater Hypnotist becomes untapped, target creature an opponent controls gets -3/-0 until end of turn.

Boomerang

Return target permanent to its owner's hand.

Merfolk Falconer

Flying
Whenever you cast a kicked spell, scry 2.

Serpentine Curve

Create a 0/0 green and blue Fractal creature token. Put X +1/+1 counters on it, where X is one plus the total number of instant and sorcery cards you own in exile and in your graveyard.

Urza's Rebuff

Choose one —
• Counter target spell.
• Tap up to two target creatures.

Seafloor Stalker

{4}{U}: Seafloor Stalker gets +1/+0 until end of turn and can't be blocked this turn. This ability costs {1} less to activate for each creature in your party. (Your party consists of up to one each of Cleric, Rogue, Warrior, and Wizard.)

Vodalian Arcanist

{T}: Add {C}. Spend this mana only to cast an instant or sorcery spell.

You Find the Villains' Lair

Choose one —
• Foil Their Scheme — Counter target spell.
• Learn Their Secrets — Draw two cards, then discard two cards.

Pop Quiz

Draw a card.
Learn. (You may reveal a Lesson card you own from outside the game and put it into your hand, or discard a card to draw a card.)

Coral Commando

Gray Harbor Merfolk

Gray Harbor Merfolk can't be blocked.
Gray Harbor Merfolk gets +2/+0 as long as you control a commander that's a creature or planeswalker.

Sea's Claim

Enchant land (Target a land as you cast this. This card enters attached to that land.)
Enchanted land is an Island.

Teferi's Tutelage

When Teferi's Tutelage enters, draw a card, then discard a card.
Whenever you draw a card, target opponent mills two cards. (They put the top two cards of their library into their graveyard.)

Surgical Skullbomb

{1}, Sacrifice Surgical Skullbomb: Draw a card.
{2}{U}, Sacrifice Surgical Skullbomb: Return target creature to its owner's hand. Draw a card. Activate only as a sorcery.

Storm Sculptor

Storm Sculptor can't be blocked.
When Storm Sculptor enters, return a creature you control to its owner's hand.

Coralhelm Guide

{4}{U}: Target creature can't be blocked this turn.

Sage of the Falls

Whenever Sage of the Falls or another non-Human creature you control enters, you may draw a card. If you do, discard a card.

Voda Sea Scavenger

Domain — When Voda Sea Scavenger enters, look at the top X cards of your library, where X is the number of basic land types among lands you control. You may put one of those cards on top of your library. Put the rest on the bottom of your library in a random order.

Lonely Sandbar

Lonely Sandbar enters tapped.
{T}: Add {U}.
Cycling {U} ({U}, Discard this card: Draw a card.)

Tide Shaper

Kicker {1} (You may pay an additional {1} as you cast this spell.)
When Tide Shaper enters, if it was kicked, target land becomes an Island for as long as Tide Shaper remains on the battlefield.
Tide Shaper gets +1/+1 as long as an opponent controls an Island.

Frost Breath

Tap up to two target creatures. Those creatures don't untap during their controller's next untap step.

Merfolk Wayfinder

Flying
When Merfolk Wayfinder enters, reveal the top three cards of your library. Put all Island cards revealed this way into your hand and the rest on the bottom of your library in any order.

Flight

Enchant creature
Enchanted creature has flying.

Ichthyomorphosis

Enchant creature
Enchanted creature loses all abilities and is a blue Fish with base power and toughness 0/1.

Moonlit Scavengers

When Moonlit Scavengers enters, if you control an artifact or enchantment, return target creature an opponent controls to its owner's hand.

Talrand's Invocation

Create two 2/2 blue Drake creature tokens with flying.

Dakra Mystic

{U}, {T}: Each player reveals the top card of their library. You may put the revealed cards into their owners' graveyards. If you don't, each player draws a card.

The Surgical Bay

The Surgical Bay enters tapped.
{T}: Add {U}.
{1}{U}, {T}, Sacrifice The Surgical Bay: Draw a card.

Switcheroo

Exchange control of two target creatures.

Blatant Thievery

For each opponent, gain control of target permanent that player controls.

Wishful Merfolk

Defender
{1}{U}: Wishful Merfolk loses defender and becomes a Human until end of turn.

Svyelun of Sea and Sky

Svyelun of Sea and Sky has indestructible as long as you control at least two other Merfolk.
Whenever Svyelun attacks, draw a card.
Other Merfolk you control have ward {1}. (Whenever another Merfolk you control becomes the target of a spell or ability an opponent controls, counter it unless that player pays {1}.)

Island

Expedition Diviner

Flying
As long as you control another Wizard, Expedition Diviner has "When this creature dies, draw a card."

Shattered Ego

Enchant creature
Enchanted creature gets -3/-0.
{3}{U}{U}: Put enchanted creature into its owner's library third from the top.

Founding the Third Path

Read ahead (Choose a chapter and start with that many lore counters. Add one after your draw step. Skipped chapters don't trigger. Sacrifice after III.)
I — You may cast an instant or sorcery spell with mana value 1 or 2 from your hand without paying its mana cost.
II — Target player mills four cards.
III — Exile target instant or sorcery card from your graveyard. Copy it. You may cast the copy.

Unknown Shores

{T}: Add {C}.
{1}, {T}: Add one mana of any color.

So Tiny

Flash
Enchant creature
Enchanted creature gets -2/-0. It gets -6/-0 instead as long as its controller has seven or more cards in their graveyard.

Contentious Plan

Proliferate. (Choose any number of permanents and/or players, then give each another counter of each kind already there.)
Draw a card.

Triton Shorestalker

Lord of Atlantis

Other Merfolk get +1/+1 and have islandwalk. (They can't be blocked as long as defending player controls an Island.)

Blockade Runner

{U}: Blockade Runner can't be blocked this turn.

Master of the Pearl Trident

Other Merfolk creatures you control get +1/+1 and have islandwalk. (They can't be blocked as long as defending player controls an Island.)

Rootwater Commando

Islandwalk (This creature can't be blocked as long as defending player controls an Island.)

Counterspell

Spontaneous Mutation

Flash
Enchant creature
Enchanted creature gets -X/-0, where X is the number of cards in your graveyard.

Tazeem Roilmage

Kicker {4} (You may pay an additional {4} as you cast this spell.)
When Tazeem Roilmage enters, if it was kicked, return target instant or sorcery card from your graveyard to your hand.

Defabricate

Choose one —
• Counter target artifact or enchantment spell. If a spell is countered this way, exile it instead of putting it into its owner's graveyard.
• Counter target activated or triggered ability.

Raving Visionary

{U}, {T}: Draw a card, then discard a card.
Delirium — {2}{U}, {T}: Draw a card. Activate only if there are four or more card types among cards in your graveyard.

Cascade Seer

When Cascade Seer enters, scry X, where X is the number of creatures in your party. (Your party consists of up to one each of Cleric, Rogue, Warrior, and Wizard.)

Cleric of Chill Depths

Whenever Cleric of Chill Depths blocks a creature, that creature doesn't untap during its controller's next untap step.

Hard Evidence

Create a 0/3 blue Crab creature token.
Investigate. (Create a Clue token. It's an artifact with "{2}, Sacrifice this artifact: Draw a card.")

Watertrap Weaver

When Watertrap Weaver enters, tap target creature an opponent controls. That creature doesn't untap during its controller's next untap step.

Crashing Tide

This spell has flash as long as you control a Merfolk.
Return target creature to its owner's hand.
Draw a card.

Shipwreck Dowser

Prowess (Whenever you cast a noncreature spell, this creature gets +1/+1 until end of turn.)
When this creature enters, return target instant or sorcery card from your graveyard to your hand.

Split the Party

Choose target player. Return half the creatures they control to their owner's hand, rounded up.

Wavecrash Triton

Heroic — Whenever you cast a spell that targets Wavecrash Triton, tap target creature an opponent controls. That creature doesn't untap during its controller's next untap step.

Venture Deeper

Target player mills four cards. (Then exile this card. You may cast the creature later from exile.)